The disclosed invention generally relates to sensing systems, and is more particularly directed to a sensing system having passive elements in its transducer.
Sensing systems may be utilized in applications where one or more parameters (e.g., pressure or temperature) is sensed at a location that is remote from the readout device. For example, pressure and temperature sensing systems are utilized in oil and gas wells to provide pressure and temperature information, sometimes sensed at the well-head and/or down-hole. Such sensing systems may be utilized to optimize production efficiency, and to determine operating parameters that are useful in assessing the well's performance status.
Known pressure and/or pressure sensing systems, such as those used in oil wells, typically include active devices (e.g., transistors) in the transducer and its associated components. In oil well applications, the transducer (i.e., the sensing element for sensing pressure or temperature) is sometimes located down-hole, and is therefore subjected to a very harsh environment. Downhole transducers that utilize active devices generally have limited lifetimes due to the harsh environment, and moreover are very difficult and costly to replace. As a result, they typically do not get replaced, and the oil wells are operated without the benefit of pressure and temperature information.
A further consideration with known sensing systems that utilize active devices in their transducers and which are utilized in a harsh environment is drift. Such consideration is particularly important in applications such as oil wells where access to the transdueers is difficult and costly after installation.
A further consideration with known pressure or temperature sensing systems having transducers that utilize active devices is the necessity of providing power to the active devices. In the case where the transducer is placed down down-hole, the power must be supplied down-hole, thus posing another possible failure mode through breakage of the power-supplying electrical conductors, or poor contacts in their electrical connectors.